Controls: hide Surface section in heatmap / diff modes

The `Surface` drawer section drives `IsosurfaceRenderer` /
`VolumeRenderer`; in heatmap mode (the default) and signed-diff mode
(`s=d`) the render branch is `HeatmapRenderer`, which ignores
`isoLevel`. The section was permanently visible as dead UI — sliding
Iso or Opacity had no effect on the rendered scene.

- `Controls.tsx`: gate the `Surface` `DrawerSection` on `!useHeatmap
  && !isDiff`. New `isDiff?: boolean` prop, plumbed from `App.tsx` as
  `srcRole === 'diff'`.
- `e2e/elvis.spec.ts:waitForLoad`: previously probed `Iso: \d+` text
  (which lived inside Surface) as the "data parsed" signal. Switched
  to `window.__elvisCameraReady`, the explicit camera-mounted flag
  CameraController already sets after a frame post-render. Robust to
  further section-visibility changes.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: ryan-williams

pkgs/core/src/components/Controls.tsx

@@ -77,6 +77,9 @@ interface ControlsProps {
   highlightElement?: string | null
   /** Called when the user hovers/unhovers an element pill in the legend */
   onHighlightElementChange?: (el: string | null) => void
+  /** Whether the current view is a signed diff (`s=d`). Hides the Surface
+   *  section since Iso/Opacity don't apply to the heatmap-only diff render. */
+  isDiff?: boolean
   /** Heatmap-mode params (only meaningful when heatmap mode is on). */
   useHeatmap?: boolean
   onUseHeatmapChange?: (v: boolean) => void
@@ -165,6 +168,7 @@ export function Controls({
   onTileFadeChange,
   highlightElement: _highlightElement,
   onHighlightElementChange,
+  isDiff,
   useHeatmap,
   onUseHeatmapChange,
   heatmapOpacity = 0.4,
@@ -281,6 +285,7 @@ export function Controls({
         </div>
       )}
 
+      {!useHeatmap && !isDiff && (
       <DrawerSection id="surface" title="Surface" icon={<Atom size={ICON_SIZE} />} accent={ACCENT.surface} defaultOpen>
           <div className={styles.controlLabel}>
             <div className={styles.sliderHeader}>
@@ -347,6 +352,7 @@ export function Controls({
             />
           </div>
         </DrawerSection>
+      )}
 
       {onUseHeatmapChange && (
         <DrawerSection id="heatmap" title="Heatmap" icon={<Flame size={ICON_SIZE} />} accent={ACCENT.heatmap} defaultOpen={false}>

pkgs/static/e2e/elvis.spec.ts

@@ -51,10 +51,14 @@ async function waitForLoad(page: Page) {
   // The filename appears in the (default-closed) Cached Files drawer as well as
   // the always-visible Controls panel title; `.last()` picks the visible one.
   await expect(page.getByText('mp-1000020.json.gz').last()).toBeVisible({ timeout: 15000 })
-  // Iso info shows after grid data is parsed and density quantiles computed.
-  // Replaces the previous `Slice: X / 31` probe, which no longer renders since
-  // slice display defaults off (a40b788).
-  await expect(page.getByText(/Iso: \d+/)).toBeVisible({ timeout: 10000 })
+  // CameraController sets `__elvisCameraReady` only after the renderer is
+  // mounted (which requires parsed volume data). Robust to UI changes that
+  // move/hide individual controls — previously this probed `Iso: \d+` inside
+  // the Surface section, which now hides in heatmap (default) mode.
+  await page.waitForFunction(
+    () => (window as unknown as { __elvisCameraReady?: boolean }).__elvisCameraReady === true,
+    { timeout: 10000 },
+  )
 }
 
 /** Enter slice mode and wait for the keymap to be active. */

pkgs/static/src/App.tsx

@@ -1792,6 +1792,7 @@ export default function App() {
         {primaryFile && (
           <ErrorBoundary label="Controls" resetKey={`${materialId}:${effectiveIsoLevel}`}>
             <Controls
+              isDiff={srcRole === 'diff'}
               isoLevel={effectiveIsoLevel}
               defaultIsoLevel={defaultIsoLevel}
               maxDensity={maxDensity}